According to the classic doctrine of angiosperm evolution,the archetype carpel in angiosperms is of plicate form.However,this concept is facing increasing challenges from the systematics based on molecular data,which ...According to the classic doctrine of angiosperm evolution,the archetype carpel in angiosperms is of plicate form.However,this concept is facing increasing challenges from the systematics based on molecular data,which now takes ascidiate carpel as ancestral.This reorientation in evolutionary thinking cannot be fully achieved unless there is supporting fossil evidence.Here a fruit, named Liaoningfructus,is reported from the famous Yixian Formation(Early Cretaceous,125 Ma), which yielded several pioneer angiosperms in the past decades.The configuration of the fruit suggests that the carpel giving rise to the fruit is most likely ascidiate,favoring the above reorientation.There are two seeds in the fruit,and at least one of them is served by a vascular bundle arising from the bottom of the fruit,implying a basal placentation in the former carpel,which again is different from the classic thinking.This discovery not only enhances the diversity of angiosperms in the Yixian Formation,but also accelerates the on-going switching of thinking on angiosperm evolution.展开更多
Sex determination in plants gives rise to unisexual flowers that facilitate outcrossing and enhance genetic diversity. In cucumber and melon, ethylene promotes carpel development and arrests sta- men development. Five...Sex determination in plants gives rise to unisexual flowers that facilitate outcrossing and enhance genetic diversity. In cucumber and melon, ethylene promotes carpel development and arrests sta- men development. Five sex-determination genes have been identified, including four encoding 1-aminocyclopropane-l-carboxylate （ACC） synthase that catalyzes the rate-limiting step in ethylene biosynthesis, and a transcription factor gene CmWIP1 that corresponds to the Mendelian locus gynoecious in melon and is a negative regulator of femaleness. ACC oxidase （ACO） converts ACC into ethylene; how- ever, it remains elusive which ACO gene in the cucumber genome is critical for sex determination and how CmWIP1 represses development of female flowers. In this study, we discovered that mutation in an ACO gene, CsAC02, confers androecy in cucumber that bears only male flowers. The mutation disrupts the enzymatic activity of CsAC02, resulting in 50% less ethylene emission from shoot tips. CsAC02 was ex- pressed in the carpel primordia and its expression overlapped with that of CsACS11 in female flowers at key stages for sex determination, presumably providing sufficient ethylene required for proper CsACS2 expression. CmAC03, the ortholog of CsACO2, showed a similar expression pattern in the carpel region, suggesting a conserved function of CsACO2/CmACO3. We demonstrated that CsWlP1, the ortholog of CmWlP1, could directly bind the promoter of CsAC02 and repress its expression. Taken together, we propose a presumably conserved regulatory module consisting of WlP1 transcription factor and ACO controls unisexual flower development in cucumber and melon.展开更多
Diclinism is not only an interesting natural phenomenon in plant kingdom, but also of significance in the yield of crops, e.g. cucumber and watermelon. Cucumber has been a model plant for studying the diclinism for de...Diclinism is not only an interesting natural phenomenon in plant kingdom, but also of significance in the yield of crops, e.g. cucumber and watermelon. Cucumber has been a model plant for studying the diclinism for decades. However, it is stili obscure how the carpel primordia of cucumber male flower undergo the developmental processes after the initiation of their development. By showing morphological alternation, metabolic activity, as well as CFL gene expression, the present study demonstrated that the carpel primordia of cucumber male flowers maintained the characteristics of primordium until anthesis, although it developed significantly slower than that of the female flowers.展开更多
The flower is an evolutionary innovation in angiosperms that drives the evolution of biodiversity.The carpel is integral to a flower and develops into fruits after fertilization,while the perianth,consisting of the ca...The flower is an evolutionary innovation in angiosperms that drives the evolution of biodiversity.The carpel is integral to a flower and develops into fruits after fertilization,while the perianth,consisting of the calyx and corolla,is decorative to facilitate pollination and protect the internal organs,including the carpels and stamens.Therefore,the nature of flower origin is carpel and stamen origin,which represents one of the greatest and fundamental unresolved issues in plant evolutionary biology.Here,we briefly summarize the main progress and key genes identified for understanding floral development,focusing on the origin and development of the carpels.Floral ABC models have played pioneering roles in elucidating flower development,but remain insufficient for resolving flower and carpel origin.The genetic basis for carpel origin and subsequent diversification leading to fruit diversity also remains elusive.Based on current research progress and technological advances,simplified floral models and integrative evolutionary-developmental(evodevo)strategies are proposed for elucidating the genetics of carpel origin and fruit evolution.Stepwise birth of a few master regulatory genes and subsequent functional diversification might play a pivotal role in these evolutionary processes.Among the identified transcription factors,AGAMOUS(AG)and CRABS CLAW(CRC)may be the two core regulatory genes for carpel origin as they determine carpel organ identity,determinacy,and functionality.Therefore,a comparative identification of their protein-protein interactions and downstream target genes between flowering and non-flowering plants from an evo-devo perspective may be primary projects for elucidating carpel origin and development.展开更多
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX2-YW-154)the National Natural Science Foundation of China(40772006, 40625006,40632010 and J0630967)+1 种基金the State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology Programs (20102108,20101104)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
文摘According to the classic doctrine of angiosperm evolution,the archetype carpel in angiosperms is of plicate form.However,this concept is facing increasing challenges from the systematics based on molecular data,which now takes ascidiate carpel as ancestral.This reorientation in evolutionary thinking cannot be fully achieved unless there is supporting fossil evidence.Here a fruit, named Liaoningfructus,is reported from the famous Yixian Formation(Early Cretaceous,125 Ma), which yielded several pioneer angiosperms in the past decades.The configuration of the fruit suggests that the carpel giving rise to the fruit is most likely ascidiate,favoring the above reorientation.There are two seeds in the fruit,and at least one of them is served by a vascular bundle arising from the bottom of the fruit,implying a basal placentation in the former carpel,which again is different from the classic thinking.This discovery not only enhances the diversity of angiosperms in the Yixian Formation,but also accelerates the on-going switching of thinking on angiosperm evolution.
文摘Sex determination in plants gives rise to unisexual flowers that facilitate outcrossing and enhance genetic diversity. In cucumber and melon, ethylene promotes carpel development and arrests sta- men development. Five sex-determination genes have been identified, including four encoding 1-aminocyclopropane-l-carboxylate （ACC） synthase that catalyzes the rate-limiting step in ethylene biosynthesis, and a transcription factor gene CmWIP1 that corresponds to the Mendelian locus gynoecious in melon and is a negative regulator of femaleness. ACC oxidase （ACO） converts ACC into ethylene; how- ever, it remains elusive which ACO gene in the cucumber genome is critical for sex determination and how CmWIP1 represses development of female flowers. In this study, we discovered that mutation in an ACO gene, CsAC02, confers androecy in cucumber that bears only male flowers. The mutation disrupts the enzymatic activity of CsAC02, resulting in 50% less ethylene emission from shoot tips. CsAC02 was ex- pressed in the carpel primordia and its expression overlapped with that of CsACS11 in female flowers at key stages for sex determination, presumably providing sufficient ethylene required for proper CsACS2 expression. CmAC03, the ortholog of CsACO2, showed a similar expression pattern in the carpel region, suggesting a conserved function of CsACO2/CmACO3. We demonstrated that CsWlP1, the ortholog of CmWlP1, could directly bind the promoter of CsAC02 and repress its expression. Taken together, we propose a presumably conserved regulatory module consisting of WlP1 transcription factor and ACO controls unisexual flower development in cucumber and melon.
文摘Diclinism is not only an interesting natural phenomenon in plant kingdom, but also of significance in the yield of crops, e.g. cucumber and watermelon. Cucumber has been a model plant for studying the diclinism for decades. However, it is stili obscure how the carpel primordia of cucumber male flower undergo the developmental processes after the initiation of their development. By showing morphological alternation, metabolic activity, as well as CFL gene expression, the present study demonstrated that the carpel primordia of cucumber male flowers maintained the characteristics of primordium until anthesis, although it developed significantly slower than that of the female flowers.
基金supported by grants from the National Natural Science Foundation of China(31930007)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB27010106)the K.C.Wong Education Foundation(GJTD-2020-05)。
文摘The flower is an evolutionary innovation in angiosperms that drives the evolution of biodiversity.The carpel is integral to a flower and develops into fruits after fertilization,while the perianth,consisting of the calyx and corolla,is decorative to facilitate pollination and protect the internal organs,including the carpels and stamens.Therefore,the nature of flower origin is carpel and stamen origin,which represents one of the greatest and fundamental unresolved issues in plant evolutionary biology.Here,we briefly summarize the main progress and key genes identified for understanding floral development,focusing on the origin and development of the carpels.Floral ABC models have played pioneering roles in elucidating flower development,but remain insufficient for resolving flower and carpel origin.The genetic basis for carpel origin and subsequent diversification leading to fruit diversity also remains elusive.Based on current research progress and technological advances,simplified floral models and integrative evolutionary-developmental(evodevo)strategies are proposed for elucidating the genetics of carpel origin and fruit evolution.Stepwise birth of a few master regulatory genes and subsequent functional diversification might play a pivotal role in these evolutionary processes.Among the identified transcription factors,AGAMOUS(AG)and CRABS CLAW(CRC)may be the two core regulatory genes for carpel origin as they determine carpel organ identity,determinacy,and functionality.Therefore,a comparative identification of their protein-protein interactions and downstream target genes between flowering and non-flowering plants from an evo-devo perspective may be primary projects for elucidating carpel origin and development.
